This invention relates generally to electrical filters and more particularly the invention relates to a linear phase filter using programmable operational transconductance amplifiers.
In recovering signals stored optically or magnetically on a tape or disk, pulse shaping and filtering circuitry is required. The conventional filter for reading magnetically stored data, such as stored on tape or disk, is built with passive discrete components in a circuit which is designed for implementing only one particular phase/amplitude response and therefore for only one type of pick up head. The performance of the read channel is measured to the bit error rate and since the conventional read channel filter has a fixed response, any given filter contributes to lower the bit error rate for a particular head type only. Passive components typically used in such filters are analog devices which cannot be readily altered. However, an analog programmable seven pole Bessel type low pass filter is currently available from Silicon Systems, Tustin, Calif.